Climate change and the built environment

The construction industry has responsibilities around the mitigation of and adaptation to the impacts of climate change. Mitigation involves reducing the greenhouse gas emissions that contribute to the problem. Adaptation means designing and constructing new buildings and renovating old buildings so that they can better cope with more intense rainfall, floods and stronger winds.

The Parliamentary Commissioner for the Environment's 2015 report Preparing New Zealand for rising seas: Certainty and uncertainty estimated that about 9,000 New Zealand homes stand less than 0.5 m above spring high tide levels – at great risk of rising seas and flooding. Cities with large areas that are particularly low-lying include Napier, Lower Hutt, Christchurch and Dunedin, but smaller centres such as Whakatane are also affected. There are 43,680 homes less than 3 metres above mean high water spring – still at risk.

Flooded homes can become unliveable for long periods – for example, when sewage contaminates stormwater. Six months after the Edgecumbe floods in 2017, 500 homes could still not be reoccupied.

Insurance companies have begun adjusting policies and prices to reflect climate risks. Spokespeople have said that, because rising sea levels cannot be considered as accidents or unforeseen events, resulting damage is not insurable.

BRANZ is playing a key role in examining how climate change will impact our built environment. There are two key recommendations for climate action:

Increase energy efficiency Our research recommends that, for buildings (whether new or existing), there is a need to improve energy efficiency, decrease the energy supply carbon footprint and manage peak demand. These measures could be taken up by government and industry in a number of ways, such as:

investigating the feasibility of incorporating carbon performance into the Building Code

providing ongoing tracking of building carbon performance

providing additional, practical education resources to help consumers and the building industry better understand the implications of design choices from a carbon perspective over the building's lifetime.

Reduce embodied carbon The research also found a need to reduce the embodied carbon in construction materials, which could be done through measures such as:

greater application of environmental rating tools such as NABERSNZ and Greenstar, and tools that facilitate the evaluation of building environmental impacts, such as BRANZ's LCAQuick tool

producing less construction waste and increasing opportunities for reuse, recycling or recovery of waste

incentivising use of materials that provide lower embodied and life cycle greenhouse gas impacts.